Apparatus for annealing glass



LEBEL. 1,8%547 APPARATUS FOR ANNELNG GLASS Filed Jan. 30. 1930 2 Sheets-Sheet l Inventor w M. ma

Jan. 31p 1933.-

His 47 Jan. 31, 1933. H. .Ll-:BEL

i APPARATUS FOR ANNEALING GLASS Filed'Jan. 5o. 195o 2 sheets-sheep 2 Henry Lebe Z7 @P1/WQ Patented dan. 31, 1933 UNITED STATES leasen PATENT y OFFICE nmmY'LnnnL, or PARIS, FRANCE, AssIGNoa To SOCIT ANONYME DES MANU- a rAcTUnns Das GLAsEs a PRODUITS CHIMIQUES :on SAINT GOBAIN; OHAUNY a CIBEY, F FABI'f, FRANCE APPARATUS ron ANNEALINb GLASS Application led January 30, 1930, Serial No. 424,669, and in France February 7, 1929.

invention relates to a method and apparatus for annealing glass, and particular.

ly a continuous.: sheet of glass.

In the formation of sheet glass and in its' transfer to the lehr, there are produced variations in temperature between different parts of the sheet, thereby setting up local stresses, particularly along the edge of the sheet\wh1ch can only be Overcome by reheating the sheet to regain the evenness of temperature throughout the entire sheet This reheating of the sheet prior to its annealino is a costly operation, because Aof the cost of: structure and length of lehr necessary to Obtain a proper reheating. The object of this and for a uniform and progressive loss of the heat within the sheet as soon as the equalities of temperature is established within the sheet to be annealed. The structure to accomplish this, is shown in the accompanying drawings in which,-

Fi re 1 is a longitudinal section 'of a forming device and lehr embodying my invention.

Figure 2 isa sectional plan view thereof.

Figure 3 is a transverse section on line 3-3 of Figure 1.

Figure 4 is a transverse section OnV the line 4-4 of Figure 1.

Figure 5 is a transverse section on the line 5 5 of Figure 1; and

Figure 6 is a transverse section on the line 6-6 of Figure 1.

In Figure 1, ais a melting tank having in close proximity thereto the forming a paratus b, which forms the continuous s eet of glass c. The sheet of glass to be annealed is conducted from the forming rolls to the lehr, which is in close relation thereto, so

the fuel involved,`*and because of the as to conserve the initial heat with the sheet of glass on the conveying rollers comprising are the openings w, through whi h heat may beinjected to bring the sheet of lass to the necessary temperature to anneal 1 if it be a very thin sheet of glass, or to heat the lehr at the beginning of a run. In the section C of the lehr the temperature of the glass is gradually decreased, whxile in the section D, the glass is exposed to artlficial cooling means, prior to the sheet being exposed to atmospheric temperature. e are the side walls of the lehr housing which pro .essively decrease in thickness to afford ecreasing \in sulation on the sides of the sheet as it moves toward the exit end of the lehr. Within the side walls e of the lehr below the sup orting rollers d2, is the flooring f, supporte On the` uprights g and lz., thus forming three horizontal channels z', j and lc runnin the length of the lehr sections A, B and floor of the lehr. y Y, under the center of thelehryprogressively increases from the entrance end of the lehr towards the exit end of, the lehr, while the channels z' and 1:, which are open under the section C, progressively increase in size towards the exit end of the lehr. In the sections A and B, the channels z' and le are lled with insulating material. The roof Z of the lehr, in the sections A, B, and part of C, is of peculiar construction, and will be now described. Above the conveying rollers d, and between the side walls of the lehr e, the roof l has the downward projection m over the center of the conveying rollers. This projection m in the roof, gradually lowers towards the supporting rollers until in the section C, where it is lat through its entire distance over the rollers. The roof over the under the The size of thechannel j,

other part of the section C of the lehr, is also fiat and is made of corrugated metal Z. Where the roof is flat, it is very close to the sheet of glass. Above the roof Z in the lehr sections A and B, are the masonry blocks n which, with the several covers p, form a conduit which can be opened to atmospheric temperature. Through this construction, the center of the sheet can be exposed to radiation in varying degrees. Above the roof Z and the side walls of the lehr e, is the insulating material 0, which gradually decreases from the entrance end of the lehr towards the exit end of the lehr and entirely disappears in the lehr section Above and below the supporting rollers d3 of the lehr section D, are the pipes g, having valves r interposed between the pipes and thesource of supply of the cooling medium. These pipes g run 1 parallel with the sheet of glass'which passes over or under them as the case may be. Their function is to'chill the glass prior to its reception into normal atmospheric temperature. The travel of the coolin iiuid in the pipes should be the reverse of t e movement of the sheet of glass through the lehr. The flow of the cooling medium can be regulated in each pipe separatel so as to correct inequalities of cooling w 'ch may arise in different parts in the same plane transverse of the sheet. The construction of the lehr in the section D, comprises only the sup orting rollers d3 and the side walls e, and t e coolin ipes g.

rough the length of the lehr and especially at the entrance and exit end of the lehr are movable fire-proof curtains or dampers u which retain the heat within the lehr an exclude cold air from the lehr. The dampers nary atmospheric temperature. `The heat-v ing or cooling in the sections is further controlled to a nicety by the construction of the lehr, so that the heating or reduction of temperature in any one section may vary in a cross section thereof. The reheatingvis accomplished in the sections A and B, by the heat within the sheet and'from that retained in that section of the lehr through the conservation of heat from hot glass that has preceded the glass being reheated, and cooled in the section C, in a decreasing manner, because of decrease in insulation in certain parts in that section of the lehr and 'ositvely cooled as a unit in the section D, y regulating the temperature which passes over and under the sheet.

It is to be noted here that the insulation within each of the sections is different, and that transverse sections differ from one another, in that they are provided with walls of different insulation, and that the walls of certain sections and parts of the lehr are given such shapes that the movements of the heated air in contact with the glass are reduced as much as possible by these constructions.

Having thus described my invention what I claim as new, and desire to secure by Letters Patent is 1. A glass annealing lehr, means for conveying glass through said lehr, a roof over said conveying means which near the entrance end of the lehr is lower in the longitudinal center over the conveying means than along the edges thereof, and progressively descends toward the exit end of the lehr and insulation on each side of said lower portion of said roof which also progressively decreases toward the exit end of the lehr.

2. The combination with a lehr structure for sheet glass having a cooling channel in its top and in its bottom adjacent to its entrance end, located in the medial longitudinal vertical plane lof the lehr and having insulation on each side of said channels along the edges of the top and bottom of the lehr, of a conveyor for moving the sheet through the lehr.

3. The combination with a lehr structure having a roof, the medial longitudinal portion of which near the entrance end of the lehr is lower than the portions on each side thereof, of a conveyor for feeding sheet glass through the lehr.

4. The combination with a lehr structure having a roof, the medial longitudinal portion of which near the entrance end of the lehr is lower than the portions on each side thereof, the said roof in the successive sections of the lehr being progressively lower,

of a conveyor for feeding sheet glass through the lehr.

5. The combination with a lehr structure having a roof, the medial longitudinal portion of which near the entranceend of the lehr is lower than the portions on each side thereof, the difference in height between the medial and side portions being less at the succeeding portions of the lehr, of a conveyor for feeding sheet glass through the lehr.

6. A glass annealing lehr having in its bottom central longitudinal and side longitudinal channels, the said channels increasing in ye'tical depth towards the exit end of the 7 A glass annealing lehr having in its bottom central longitudinal and side longitudidlehr, and t nal channels, theisaid channels increasing in vertical de th towards the exit end of the lie side channels starting further along the lehr than does the central channel.

8. In a "glass annealing lehr, means for conveying glass through said lehr, a roof over said conveying means which near the entrance end of the lehr is lower in the longitudinal center over the conveying means than along the edges thereof, and means for varying the temperature of the bottom of said lower portion of the roof.

9. In a glass annealing lehr, means for conveying glass through said lehr, a roof over said conveying means which near the entrance end of the lehr is lower in the longitudinal center over the conveying means than along the edges thereof and adJustable panels in the lower portion of the roof of the median longitudinal channel so formed to control the rate of cooling in said channel.

In testimony whereof I hereunto ax my signature.

HENRY LEBEL 

